The FTC and the Justice Department are expected to review the blockbuster deal, which would give the Menlo Park company control over one of the world’s most popular mobile phone messaging apps.

The groups want the FTC to prevent Facebook from tapping WhatsApp’s database of mobile phone numbers and other data because WhatsApp users believed the Mountain View app maker would protect their private information.

“WhatsApp users could not reasonably have anticipated that by selecting a pro-privacy messaging service, they would subject their data to Facebook’s data collection practices,” the complaint said.